The History of The Lie Detector

By Alex Horn

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1878: First plethysmograph machine is built

In 1878 an Italian physiologist named Angelo Mosso invented a machine called the plethysmograph. The machine was used to study emotions and fears by sensing their cardiovascular and respiratory activity.
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1892: The first Polygraph machine is built

In 1892 Sir James Mackenzie invented the polygraph machine. It is unlike the modern polygraph however because this version is used for medical stuff.
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1895: The first "deception detection" machine is built

In 1895 an Italian physician and psychiatrist modified a hydrosphygmograph to make it detect lies. The machine worked by recording a pulse, if the pulse went up, the subject was lying, if it didn't, they were being honest.
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1914: A method for inhalation to exhalation

In 1914 another Italian Psychologist named Vittorio Benussi discovered a method for calculating the quotient of inhalation to exhalation time. This proves that breathing rate is another factor to lying.
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1915: Modern Polygraph machine is invented

An American attorney and psycologist named William Marston invents the modern polygraph machine which works by having a standard blood pressure cuff around the arm take blood pressure. This invention revolutionizes the polygraph machine's use as a lie detector.
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1921: Resperation system added to poygraph machine

A Canadian psycologist named John A. Larson modifies the polygraph machine to include a resperation system to record the patients breathing rate. This later becomes a feature added to all polygraphs.
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The mid 1940s: the interigation technique used

A lawyer from Chicago named John E. Reed developed the Control question technique (CQT). This technique uses questions that involve more description thus causing more emotion to test.
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1948: First Polygraph school founded

In 1948 Leonarde Keeler founds the first school to teach how to use a polygraph machine. This proves that the invention is here to stay and is starting to become more commonly used.
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1958: Quantitative System of Chart Analysis made

In 1958 an ex-polygraph examiner with the CIA named Cleve Backster introduced the quantification system of chart. This made the machine much more accurate and therefore more reliable.
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1992: CAPS invented

Starting in the 1980's, many doctors who worked at the University of Utah were just beginning to work on the Computer Assisted Polygraph System or CAPS. This would change the typical stylyus and paper look of the original to a more of a printer look.
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Reasoning to why this invention is important

This invention is very important especially with today's terrorism and other serious crimes. This invention helps take down the most ruthless criminals while protecting the innocent from false accusations. The Polygraph also still helps in the medical world by taking pulses constantly for patients in a coma or under serious care. The Polygraph is also very important in finding bigfoot apparently because it is used all the time in tv shows like that. As a conclusion, the Polygraph Machine (lie detector) has revolutionized the justice system, the medical world, and even tv.


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